CVE-2026-105830: Uncontrolled Resource Consumption in thephpleague commonmark
Description
league/commonmark from 2.0.0 before 2.10.2 contains a quadratic-time denial of service vulnerability in the GitHub Flavored Markdown Table extension's TableStartParser::tryStart() block-start scan. Unauthenticated attackers can submit a large paragraph of pipe-free lines not starting with letters, forcing repeated full-buffer strpos scans that exhaust PHP worker CPU.
CVSS v4.0
Score 8.7high
Affected software
thephpleague
commonmark
pkg:composer/thephpleague/commonmarkRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Thephpleague commonmark library versions >=2.0.0 and <2.10.2 contain a quadratic-time denial of service vulnerability in the GitHub Flavored Markdown Table extension. Specifically, the TableStartParser::tryStart() method performs a block-start scan that can be forced into repeated full-buffer strpos operations by unauthenticated attackers submitting large paragraphs of pipe-free lines not starting with letters. This results in uncontrolled CPU resource consumption, potentially exhausting PHP worker CPU resources.
Potential Impact
An unauthenticated attacker can cause a denial of service by exhausting CPU resources on the server running the vulnerable commonmark library. This can degrade or disrupt service availability due to high CPU usage caused by the quadratic-time processing of crafted input.
Mitigation Recommendations
A fix is available in version 2.10.2 of thephpleague commonmark. Users should upgrade to version 2.10.2 or later to remediate this vulnerability. Patch status is confirmed by the version range indicating fixed in 2.10.2.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-10-05T21:59:09.591Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ac7a6672cdf04f6561df638
Added to database: 10/08/2026, 14:19:19 UTC
Last enriched: 10/08/2026, 14:35:29 UTC
Last updated: 10/08/2026, 17:36:25 UTC
Views: 10
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